The Xiaomi 1S portable electric compressor goes to less than 40 euros on AliExpress. The compressor allows you to inflate and re-inflate all everyday objects, from your car tires to air mattresses.
It can be used with hydraulic mountain bike shock absorbers, but also high-pressure road bike tires. The wireless compressor works on a rechargeable battery, and once charged, allows to completely inflate 2 car tires, or to reinflate them and complete the necessary air, up to 8 times.